Exemplary embodiments of the present invention relate to a device for connecting a line element to a component and a fuel cell system having at least one component comprising such a line element.
German Patent Document DE 10 2007 009 898 A1 discloses a heating system for a pipe or a tube in a fuel cell system. A heating wire in contact with the pipe or tube in order to prevent water from freezing in the pipe or tube. The heating wire is, for example, wound around the pipe or tube and is fixed thereto via a protective layer. In addition, a thermal insulation can be provided.
The problem with this structure is that the pipe itself can be heated. Heating is thereby difficult in the region of possible connection elements, in particular if the heated line element is attached to an unheated component, for example a fuel cell stack, a reactor, a water separator or similar. Condensation and freezing of liquid water can then arise in this region, as merely the surrounding pipelines can be heated and this region of the connection is not heated.
Exemplary embodiments of the present invention provide a device for connecting a line element to a component that is designed so that the abovementioned disadvantages are avoided and a connection is ensured that avoids the condensation and possible freezing of liquid from the medium conveyed in the line element.
The device according to the invention for connecting a line element to a component is configured so that the line element ends in a connection housing or is fixedly connected to such a connection housing. This connection housing itself then comprises suitable means for releasable fixing to the component. This can be, for example, a conventional screw interacting with a flange. In addition other releasable connection means would be conceivable, for example plug-in connections with mechanical locking, as described in particular by the SAE paper J 2044.
According to the invention a line section extending in the connection housing is heated via an electric heating wire externally surrounding it. The heated line section thereby projects in the direction of the component so far over the region for releasable fixing of the connection housing to the component that the line section ends in the inner space of the component.
The device according to the invention thus allows the media to be transported to also be heated in the region of the component interface or the connection of the line element to a component as well as allowing the thawing of any medium frozen in this region. As the line section projects into the inner space of the component it can additionally be ensured that condensing medium forming in the region of the possibly cool wall of the component and running down the wall does not penetrate into the line element or the line section. The secure and reliable transport of media with the line element to the component can thus be ensured.
According to an exemplary embodiment of the present invention the material of the connection housing surrounds the heated line section and the heating wire over the whole length of the line section. The heating wire can thus be wound around the line section correspondingly from externally so that no reaction of a medium conveyed in the line section with the possibly very hot heating wire can occur. In addition, due to the fact that the material of the connection housing surrounds both the heating wire and the line section, this can be correspondingly protected against damage. The connection housing or the material of the connection housing thus form a protective layer around the line section provided with the heating wire. This is then protected from mechanical damage so that the heating can be securely and reliably guaranteed.
According to a further advantageous embodiment of the device according to the invention the connection housing is formed from an electrically non-conductive material. Such a connection housing composed of an electrically non-conductive material can also provide, additionally or alternatively to the abovementioned mechanical protection of the line element and/or heating wire, an electrical insulation of the heating wire in relation to the environment so that, besides the heating wire and the line section, merely the material of the connection housing is necessary as a third layer. The structure is correspondingly simple and can be cost-effectively realized.
According to an advantageous further development of the device according to the invention the connection housing is formed integrally with the line element. Such a structure can be used, for example, when line elements with a pre-finished length are used in comparatively large numbers. The line element and the connection housing can then be easily formed integrally so that in the region in which the line element goes into the connection housing, no additional interfaces are produced that could be critical in terms of sealing and possibly in relation to the transmission of electrical heat energy from the region of the connection housing into the region of the line element.
According to a particularly favorable embodiment of the device according to the invention, the connection housing is formed as an injection molded part, which surrounds an end of the line element and the line section on the outer periphery. Such a structure as an injection molded part, in particular made of plastic, can be easily used to produce a comparatively stable and cost-effective connection housing if correspondingly high numbers of connection housings are required. Due to the fact that the connection housing or the injection molded material of the connection housing completely surrounds an end of the line element and the line section, a sealed connection can be produced very simply and efficiently through this structure. Additionally, the line section can be embedded together with the heating wires in the injection molded part insofar as this structure is to be used in the above-described variant. A component is then produced with a single work step on an injection molding unit which brings together all the aforementioned variants and advantages.
As already indicated above, according to a further very advantageous embodiment of the device according to the invention, the line element itself can also be designed to be electrically heated. It can thereby be particularly meaningful and advantageous if the electrical heating both of the line element and of the connection housing is designed so that the heating wire extending in the region of the line section is also connected to a heating wire extending in the region of the line element.
According to a very favorable and advantageous development of the present invention, the electrical connections for the heating wire are guided outwards in the region of the connection housing. This facilitates the electrical connection of the heating wire in the region of the connection housing. As the connection housing is releasably connected to a component, it is generally at a fixedly predefined location during the operation of a system equipped with the device and, unlike a line element formed, for example, as a tube, is typically not moved by vibrations and the like. In this region an arrangement of the electrical connection elements can thereby take place comparatively simply, securely and reliably without these being exposed to the risk of damage through constant movements.
As already mentioned above, the present invention is also directed to a fuel cell system having at least one component. This fuel cell system according to the invention then provides that the at least one component is connected by means of a device according to one of the already-described embodiments to a line element. As already known from the abovementioned prior art, it is particularly critical in fuel cell systems, in which water is produced or required in a highly pure form as product water and for moistening membranes, if these systems are operated at temperatures below freezing point. However, as this is unavoidable in vehicles in many regions of the world, the device designed according to the invention plays a particularly advantageous role in such fuel cell systems.